These spiders occur in the warmer parts of the world, Australia, Asia, Africa and America. In North America the species is Nephila clavipes.
The name Golden orb spider comes from the fact that their webs have a golden colour which glows in the sunlight. Some scientist believe the colour acts as a cammoflage against the plant voliage, others say it attracts insects such as bees and butterflies.
Nephila venom is potent but not lethat to humans.
Attempts have been made to cultivate Golden orb spiders in the same way as silk worms, but without succes. Nephila silk has been used in tissue engineering, it's biocompatibility promotes cell adhesion and proliferation, especially in peripheral nerve growth.
In Japanese volklore it is believed that Nephila can shapeshift and change into an attractive woman. Just remember that if you should come across one of these, the female spider always eats it's mate!
The photo below is of a Golden orb spider taken in the Siringa tree just next to my cottage. If you click on the photo to enlarge it you can see the gleaming golden strands. The web of this particular spider was about one meter in diameter. The spiders you see in the background, each in their own webs are equally large.
Golden orb spiders are thought to be becoming scarcer, this lot in my tree don't seem to know that.
Nephila oilipes Giant wood spider. The small ones are males.
Above Nephila maculata
Above, Nephila clavipes
Source, information and pictures except the first one. Wkipedia and www.wildlifeextra.com